Just in case this helps someone Googling around – if you are trying to install Solaris 10/08 on VirtualBox and find its taking forever and throwing Java errors – increase the RAM on the virtual machine to around a gig. Using the default 512Mb I was having all sorts of problems.
I highly recommend giving Solaris a whirl. Especially if your interested in storage – ZFS is a rather good filesystem and well worth playing with. Recent developments are making it a viable desktop solution – hopefully there will be more interesting features in the future to help it stick out from the crowd.